Lighting accounts for one-fifth of global electricity consumption1. Single materials with efficient and stable white-light emission are ideal for lighting applications, but photon emission covering the entire visible spectrum is difficult to achieve using a single material. Metal halide perovskites have outstanding emission properties2,3; however, the best-performing materials of this type contain lead and have unsatisfactory stability. Here we report a lead-free double perovskite that exhibits efficient and stable white-light emission via self-trapped excitons that originate from the Jahn–Teller distortion of the AgCl6 octahedron in the excited state. By alloying sodium cations into Cs2AgInCl6, we break the dark transition (the inversion-symmetry-induced parity-forbidden transition) by manipulating the parity of the wavefunction of the self-trapped exciton and reduce the electronic dimensionality of the semiconductor4. This leads to an increase in photoluminescence efficiency by three orders of magnitude compared to pure Cs2AgInCl6. The optimally alloyed Cs2(Ag0.60Na0.40)InCl6 with 0.04 per cent bismuth doping emits warm-white light with 86 ± 5 per cent quantum efficiency and works for over 1,000 hours. We anticipate that these results will stimulate research on single-emitter-based white-light-emitting phosphors and diodes for next-generation lighting and display technologies.
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The datasets analysed during the study are available from the corresponding authors upon request.
Sun, Y. et al. Management of singlet and triplet excitons for efficient white organic light-emitting devices. Nature 440, 908–912 (2006).
Tan, Z. K. et al. Bright light-emitting diodes based on organometal halide perovskite. Nat. Nanotechnol. 9, 687–692 (2014).
Cho, H. et al. Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes. Science 350, 1222–1225 (2015).
Xiao, Z. et al. Searching for promising new perovskite-based photovoltaic absorbers: the importance of electronic dimensionality. Mater. Horiz. 4, 206–216 (2017).
Kojima, A., Teshima, K., Shirai, Y. & Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131, 6050–6051 (2009).
Burschka, J. et al. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499, 316–319 (2013).
Lee, M. M., Teuscher, J., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643–647 (2012).
Yin, W. J., Shi, T. & Yan, Y. Unique properties of halide perovskites as possible origins of the superior solar cell performance. Adv. Mater. 26, 4653–4658 (2014).
Protesescu, L. et al. Nanocrystals of cesium lead halide perovskites (CsPbX3, X=Cl, Br, and I): novel optoelectronic materials showing bright emission with wide color gamut. Nano Lett. 15, 3692–3696 (2015).
Zhou, Q. et al. In situ fabrication of halide perovskite nanocrystal embedded polymer composite films with enhanced photoluminescence for display backlights. Adv. Mater. 28, 9163–9168 (2016).
Wang, N. et al. Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells. Nat. Photon. 10, 699–704 (2016).
Yuan, M. et al. Perovskite energy funnels for efficient light-emitting diodes. Nat. Nanotechnol. 11, 872–877 (2016).
Yang, X. et al. Efficient green light-emitting diodes based on quasi-two-dimensional composition and phase engineered perovskite with surface passivation. Nat. Commun. 9, 570 (2018); correction 9, 1169 (2018).
Zhao, B. et al. High-efficiency perovskite-polymer bulk heterostructure light-emitting diodes. Preprint at https://arxiv.org/abs/1804.09785 (2018).
Dohner, R. E., Hoke, T. K. & Karunadasa, I. H. Self-assembly of broadband white-light emitters. J. Am. Chem. Soc. 136, 1718–1721 (2014).
Song, K. S. & Williams, R. T. Self-Trapped Excitons (Springer, New York, 2008).
Smith, M. D. & Karunadasa, H. I. White-light emission from layered halide perovskites. Acc. Chem. Res. 51, 619–627 (2018).
Ueta, M., Kanzaki H., Kobayashi K., Toyozawa Y. & Hanamura E. in Excitonic Processes in Solids 309–369 (Springer, Berlin, Heidelberg, 1986).
Dohner, R. E., Jaffe, A., Bradshaw, R. L. & Karunadasa, I. H. Intrinsic white-light emission from layered hybrid perovskites. J. Am. Chem. Soc. 136, 13154–13157 (2014).
Mao, L., Wu, Y., Stoumpos, C. C., Wasielewski, M. R. & Kanatzidis, M. G. White-light emission and structural distortion in new corrugated two-dimensional lead bromide perovskites. J. Am. Chem. Soc. 139, 5210–5215 (2017).
Zhou, C. et al. Luminescent zero-dimensional organic metal halide hybrids with near-unity quantum efficiency. Chem. Sci. 9, 586–593 (2018).
Volonakis, G. et al. Cs2InAgCl6: a new lead-free halide double perovskite with direct band gap. J. Phys. Chem. Lett. 8, 772–778 (2017).
Zhao, X. G. et al. Cu–In halide perovskite solar absorbers. J. Am. Chem. Soc. 139, 6718–6725 (2017).
Meng, W. et al. Parity-forbidden transitions and their impact on the optical absorption properties of lead-free metal halide perovskites and double perovskites. J. Phys. Chem. Lett. 8, 2999–3007 (2017).
Huang, K. & Rhys, A. Theory of light absorption and non-radiative transitions in F-centres. Proc. R. Soc. Lond. A 204, 406–423 (1950).
Lim, T.-W. et al. Insights into cationic ordering in Re-based double perovskite oxides. Sci. Rep. 6, 19746 (2016).
Maughan, A. E. et al. Defect tolerance to intolerance in the vacancy-ordered double perovskite semiconductors Cs2SnI6 and Cs2TeI6. J. Am. Chem. Soc. 138, 8453–8464 (2016).
Yuan, Z. et al. One-dimensional organic lead halide perovskites with efficient bluish white-light emission. Nat. Commun. 8, 14051 (2017).
Kim, J.-H. et al. White electroluminescent lighting device based on a single quantum dot emitter. Adv. Mater. 28, 5093–5098 (2016).
Moser, F. & Lyu, S. Luminescence in pure and I-doped AgBr crystals. J. Lumin. 3, 447–458 (1971).
Dai, X. et al. Solution-processed, high-performance light-emitting diodes based on quantum dots. Nature 515, 96–99 (2014).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Kresse, G. & Furthmüller, J. Efficiency of ab initio total energy calculations for metals and semiconductors using a plane wave basis set. Comput. Mater. Sci. 6, 15 (1996).
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).
Perdew, J. P., Ernzerhof, M. & Burke, K. Rationale for mixing exact exchange with density functional approximations. J. Chem. Phys. 105, 9982–9985 (1996).
Perdew, J., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
Klimeš, J., Kaltak, M. & Kresse, G. Predictive GW calculations using plane waves and pseudopotentials. Phys. Rev. B 90, 075125 (2014).
Mostofi, A. A. et al. wannier90: a tool for obtaining maximally-localised Wannier functions. Comput. Phys. Commun. 178, 685–699 (2008).
Cappellini, G. et al. Model dielectric function for semiconductors. Phys. Rev. B 47, 9892 (1993).
Kowalczyk, T., Tsuchimochi, T., Chen, P. T., Top, L. & Van Voorhis, T. Excitation energies and Stokes shifts from a restricted open-shell Kohn–Sham approach. J. Chem. Phys. 138, 164101 (2013).
Filatov, M. & Shaik, S. A spin-restricted ensemble-referenced Kohn–Sham method and its application to diradicaloid situations. Chem. Phys. Lett. 304, 429–437 (1999).
Frank, I., Hutter, J., Marx, D. & Parrinello, M. Molecular dynamics in low-spin excited states. J. Chem. Phys. 108, 4060–4069 (1998).
Hutter, J., Iannuzzi, M., Schiffmann, F. & Vandevondele, J. Cp2k: atomistic simulations of condensed matter systems. Wiley Interdiscip. Rev. Comput. Mol. Sci. 4, 15–25 (2014).
VandeVondele, J. & Hutter, J. Gaussian basis sets for accurate calculations on molecular systems in gas and condensed phases. J. Chem. Phys. 127, 114105 (2007).
Goedecker, S., Teter, M. & Hutter, J. Separable dual-space Gaussian pseudopotentials. Phys. Rev. B 54, 1703–1710 (1996).
Perdew, J. P. & Zunger, A. Self-interaction correction to density-functional approximations for many-electron systems. Phys. Rev. B 23, 5048–5079 (1981).
VandeVondele, J. & Sprik, M. A molecular dynamics study of the hydroxyl radical in solution applying self-interaction-corrected density functional methods. Phys. Chem. Chem. Phys. 7, 1363 (2005).
d’Avezac, M., Calandra, M. & Mauri, F. Density functional theory description of hole-trapping in SiO2: a self-interaction-corrected approach. Phys. Rev. B 71, 205210 (2005).
Alkauskas, A., Lyons, J. L., Steiauf, D. & Van De Walle, C. G. First-principles calculations of luminescence spectrum line shapes for defects in semiconductors: the example of GaN and ZnO. Phys. Rev. Lett. 109, 267401 (2012).
Ruhoff, P. T. Recursion relations for multi-dimensional Franck–Condon overlap integrals. Chem. Phys. 186, 355–374 (1994).
Stadler, W. et al. Optical investigations of defects in Cd1−xZnxTe. Phys. Rev. B 51, 10619 (1995).
Nandakumar, P. et al. Optical absorption and photoluminescence studies on CdS quantum dots in Nafion. J. Appl. Phys. 91, 1509–1514 (2002).
Türck, V. et al. Effect of random field fluctuations on excitonic transitions of individual CdSe quantum dots. Phys. Rev. B 61, 9944 (2000).
Zhao, H. et al. Energy-dependent Huang–Rhys factor of free excitons. Phys. Rev. B 68, 125309 (2003).
Lao, X. et al. Luminescence and thermal behaviors of free and trapped excitons in cesium lead halide perovskite nanosheets. Nanoscale 10, 9949–9956 (2018).
McCall, K. M. et al. Strong electron−phonon coupling and self-trapped excitons in the defect halide perovskites A3M2I9 (A=Cs, Rb; M=Bi, Sb). Chem. Mater. 29, 4129–4145 (2017).
Leung, C. H. & Song, K. S. On the luminescence quenching of F centers in alkali halides. Solid State Commun. 33, 907 (1980).
Mulazzi, E. & Terzi, N. Evaluation of the Huang–Rhys factor and the half-width of F-band in KCl and NaCl crystals. J. Phys. Colloq. 28, 49–54 (1967).
Schulz, M. et al. Intensity dependent effects in silver chloride: bromine-bound exciton and biexciton states. Phys. Status Solidi B 177, 201–212 (1993).
Andrews, L. J. et al. Thermal quenching of chromium photoluminescence in ordered perovskites. I. Temperature dependence of spectra and lifetimes. Phys. Rev. B 34, 2735 (1986).
This work was financially supported by the National Natural Science Foundation of China (51761145048 and 61725401), the National Key R&D Program of China (2016YFB0700702, 2016YFA0204000 and 2016YFB0201204), the HUST Key Innovation Team for Interdisciplinary Promotion (2016JCTD111) and the Program for JLU Science and Technology Innovative Research Team. The calculation of broadband emission at the University of Toledo was supported by the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science within the US Department of Energy. The analysis of the electronic properties of halide double perovskites was funded by the Office of Energy Efficiency and Renewable Energy (EERE), US Department of Energy, under award number DE-EE0006712. Part of the code development was supported by the National Science Foundation under contract number DMR-1807818. Y.Y. acknowledges support from the Ohio Research Scholar Program. For the theoretical calculations we used the resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under contract number DE-AC02-05CH11231. Y.G. and J.E. acknowledge financial support by the Australian Research Council (DP150104483) and the use of instrumentation at the Monash Centre for Electron Microscopy. The authors from HUST thank the Analytical and Testing Center of HUST and the facility support of the Center for Nanoscale Characterization and Devices, WNLO. We also thank Z. Xiao for useful discussion about emission mechanisms and some XRD measurements, as well as T. Zhai, H. Song, Y. Zhou, H. Han, X. Lu and L. Xu for providing access to some facilities.
Nature thanks C. C. Stoumpos and the other anonymous reviewer(s) for their contribution to the peer review of this work.
The authors declare no competing interests.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 Phonon band structure of Cs2AgInCl6 and the zone-centre Jahn–Teller phonon mode (inset).
The phonon band structure was calculated by the finite-difference method with the supercell approach. The consistency of the displacement pattern of the phonon eigenvector with that of the lattice distortion during STE formation, as well as the consistency of the phonon eigenfrequency with the phonon frequency fitted from the configuration coordinate diagram, confirm that the Jahn–Teller phonon mode coupled with the photoexcited excitons is responsible for the STE formation in Cs2AgInCl6. Source data
a, The broad photoluminescence (PL) spectrum of Cs2AgInCl6 measured at room temperature. b, Temperature-dependent photoluminescence spectra of pure Cs2AgInCl6. c, Fitting results of the FWHM as a function of temperature. We note that we used a relatively low-temperature region to avoid the influence of defect-assisted emission. d, The PLQY of Cs2AgInCl6. The reference was measured in an integrating sphere with a blank quartz plate. Source data
a, GW-calculated band structure. The GW bandgap is 6.42 eV. The lowest exciton, with a binding energy of 0.8 eV, is dark. The first bright exciton has a binding energy of 0.44 eV. b. Calculated optical absorption (‘Abs-theory’) and photoluminescence (‘PL-theory’) spectra are compared with experimental results (‘Abs-exp.’ and ‘PL-exp.’). Source data
a, XRD patterns of Cs2AgxNa1−xInCl6, shifted to lower degrees with increasing sodium substitution (theta, diffraction angle). b, Refined lattice parameter, plotted as a function of the nominal x in Cs2AgxNa1−xInCl6, showing a linear increase with increased sodium substitution (see Supplementary Fig. 3 for details of the characterization). We note that selected-area electron diffraction and scanning electron nanobeam diffraction analysis results (Supplementary Figs. 4, 5) suggest the existence of a microscopic super-lattice (Na/Ag ordering). Source data
a, Photoluminescence spectra of pure Cs2AgInCl6 and Li-doped Cs2AgInCl6. b, Photoluminescence spectra of pure Cs2AgSbCl6 and Na-doped Cs2AgSbCl6. Source data
a, High-resolution single-crystal XRD of the (111) peaks of Cs2Ag0.60Na0.40InCl6 with and without Bi doping. b, Absorption spectra of various materials with and without Bi doping for wavelengths of 500–950 nm. c, PLQY results. d, Photoluminescence lifetime. e, Comparison of the total density of states (DOS) between pure and Bi-doped Cs2AgInCl6. The inset shows the band alignment of pure and Bi-doped Cs2AgInCl6. CBM, conduction band minimum; VBM, valence band maximum. The small shallow peak marked by an arrow is derived from the Bi 6s states, which hybridize with the Ag 4d states. f, Partial density of states (PDOS) of Bi-doped Cs2AgInCl6. Source data
This file contains the Supplementary Tables (Tables S1–S4) and Supplementary Discussion (Figs. S1–S17) which include: XRD analysis of alloyed Cs2AgxNa1−xInCl6 powder, inductively coupled plasma optical emission spectrometer (ICP-OES) results of Cs2AgxNa1−xInCl6 with Bi doping, electron microscopy and diffraction results of a small fraction of Cs2Ag0.60Na0.40InCl6, optical characterization of Cs2AgxNa1−xInCl6 powder, and the film morphology, device performance and further improving strategies for thermally evaporated Cs2Ag0.60Na0.40InCl6 electroluminescent devices
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Luo, J., Wang, X., Li, S. et al. Efficient and stable emission of warm-white light from lead-free halide double perovskites. Nature 563, 541–545 (2018) doi:10.1038/s41586-018-0691-0
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